The present invention relates to a washing or washing/drying machine according to the preamble of claim 1.
As it is known, drying and washing/drying machines must fulfil increasingly stringent energy consumption requirements.
In order to comply with said requirements, washing machine manufacturers must increase the energy efficiency of electromechanical systems (motors and transmission) to the highest possible extent so as to ensure minimal power consumption during operation of the machine. Said consumption cannot, however, be reduced below a given minimum threshold value. Indeed, for a given washing cycle to be performed effectively, it is always necessary to use a minimum amount of energy to heat the washing liquid and rotating the rotary drum of the washing or washing/drying machine.
To achieve a reduction below said minimum threshold value, the person skilled in the art can use energy recovery systems allowing to recover the amount of energy that has been absorbed by the machine during its operation. In this way, the overall energy consumption of the machine can be reduced: the machine must always absorb an amount of energy that is greater or equal to the minimum threshold value, but the energy recovered through energy recovery means can be subtracted from said amount.
A solution for energy recovery is described in international patent application WO 2011/045762 A1 with priority date Oct. 15, 2009 by INDESIT COMPANY S.p.A. This document describes the means for energy recovery which are capable of recovering a portion of the kinetic energy of the rotary drum by braking the latter through a motor, wherein said motor can also act as a generator.
However, said solution does not recover all the kinetic energy which is wasted during washing machine operation.